I recently learned that Google has a great collection of historical maps, including a couple that are relevant to the ongoing territorial dispute over the Senkaku / Diaoyu Islands. The best is a German map of East Asia from 1875. Pictured above is a close-up of a portion depicting the now-disputed Islands. Note the cluster of small features surrounding the one labeled “Tiao Su”—these are the Senkaku / Diaoyu. Also note the blue line running through the map—the key indicates that this represents the division between Chinese and Japanese territory.
Whoever made the map apparently thought the Islands belonged to Japan at least as early as 1875. We now know that to be an error, given that Japan didn’t annex until 1895. But the map still suggests that Chinese sovereignty was not clearly established at the time—unless the mapmakers had no clue about what was happening, the fact that they were unaware of a purported Chinese title provides at least some reason to believe that China wasn’t exercising control. This in turn supports the notion that the Islands were unoccupied terra nullius in the late 1800s, and that Japan acted lawfully in annexing them. The map is also consistent with the view that Japan genuinely perceived the Islands as unoccupied territory when it first claimed title.